nestkast

Nestkast, commonly called a nesting box, is a small, man-made cavity designed to attract and house cavity-nesting birds in gardens, parks and agricultural land. They are used to compensate for a shortage of natural tree hollows and can support local biodiversity and pest control when properly placed and maintained.

Construction and features typically involve untreated wood to avoid harmful residues, with a smooth interior and drainage holes. The entrance hole size is matched to the target species to deter larger predators and non-target species; common sizes range from about 25 to 32 millimeters in diameter. Some boxes include predator guards, drainage, ventilation, and a removable front panel for cleaning. External dimensions and internal depth are chosen to suit the intended species and climate.

Placement and use considerations include mounting on a sturdy support at a height of about 2 to 6 meters, away from heavy traffic, and sheltered from direct midday sun and strong winds. Boxes should face a relatively quiet, safe area near food sources, such as shrubs or feeders, and not be crowded with neighboring boxes to reduce competition. Regular maintenance is recommended: clean the box after each breeding season by removing old nests and debris, and check for damage or mold. Do not disturb active nests; in many jurisdictions disturbing nesting birds during the breeding season is illegal.

Nest boxes can be targeted to specific species by selecting appropriate hole sizes and perches. While they can boost local populations, occupancy varies by year and site, and boxes are most effective when part of a broader habitat improvement.